Though a common genetic blood disorder, many couples here don’t know about the potential effects of thalassemia on their baby.

During a routine prenatal check-up at her ob-gyn in 2012, Ember Zhuang was shocked when she was told to do a DNA test, together with her husband, for thalassemia, a genetic blood disorder.

Zhuang, now 39, says, “I had never heard of thalassemia until then!”

The lab report subsequently showed that her red blood cell count was out of the normal range. Fortunately, even though she has thalassemia minor, her husband does not. This meant that the risk of her baby getting thalassemia major (the lethal form of the disorder) was very low.

However, Zhuang’s cousin wasn’t as lucky. As both she and her husband are thalassemia minor carriers, their baby would have thalassemia major. So, her doctor advised her to abort her baby, as it would not survive. Luckily, they went on to have two normal children.

Although one in 20 Singaporeans have thalassemia minor, most couples have never heard of this genetic condition, according to findings from a 2020 survey by Nanyang Technological University students.

Yet, awareness of this blood disorder is important. If both partners have thalassemia minor, their offspring have a 25 per cent chance of inheriting the severe form, thalassemia major, which can cause life-threatening anaemia.

So, do consider getting screened before you try to conceive. SmartParents also has answers to important questions about this inherited blood disorder that causes your body to have less haemoglobin than normal. 

If both partners have thalassemia minor, their offspring has a 25 per cent chance of inheriting the severe form, thalassemia major, which can cause life-threatening anaemia.

What exactly is thalassemia?

Thalassemia is an inherited blood disorder caused by gene changes that affect haemoglobin production. Haemoglobin is the protein in red blood cells responsible for carrying oxygen around the body. Individuals with thalassemia are unable to produce normal haemoglobin, which gives rise to anaemia (a deficiency of healthy red blood cells).

Thalassemia comes in two main forms: Thalassemia minor and thalassemia major. Those with thalassemia minor, also known as thalassemia carriers, do not typically exhibit any symptoms or require treatment. So, they may be unaware of their condition, unless they are tested.

In contrast, thalassemia major sufferers live with life-threatening anaemia, which usually results in poor growth and a shortened lifespan, if the condition is not treated.

What is the prevalence of thalassemia in Singapore?

According to National Thalassemia Registry statistics, an estimated 1 in 20 Singaporeans (or about 5 per cent of the local population) are thalassemia carriers.

However, only 45,717 individuals have been registered as of 2018. This means that there may be over 200,000 Singaporeans who are unaware that they are thalassemia carriers.

Should couples get screened for thalassemia before they try to conceive?

It isn’t compulsory for couples to be checked for thalassemia before trying to conceive, notes Dr Beh Suan Tiong, a consultant obstetrician and gynaecologist at Thomson Medical Centre notes that

“However, it is good to couples to know if they have the genetic disorder,” he adds. “This allows them to make an informed decision, if they are found to be at risk of passing it to offspring.”

Why is thalassemia screening important?

Most healthy adults feel normal and have no symptoms even if they have thalassemia minor, Dr Beh points out.

“The majority learn about the disease when someone in the family is detected to have it and are henceforth screened. Or they find out during health screening and when they have blood tests done for various reasons.”

However, most routine blood tests may not detect any abnormality, unless it specifically tests for thalassemia.

“The main concern arises when both partners are found to have thalassemia minor, as there is a risk that the foetus may inherit both sets of abnormal genes and end up having thalassemia major, which is much more serious,” Dr Beh notes.

 

How do doctors test for thalassemia?

The doctor will do a blood test to screen for thalassemia, Dr Beh explains. The initial sample is usually tested for a full blood count and haemoglobin electrophoresis (which identifies different types of haemoglobin in the bloodstream).

If abnormalities are found, a further blood DNA analysis is required as this will give a more detailed diagnosis and information on genetic mutations.

Can couples who are planning to conceive do anything to prevent their child from getting this hereditary disease?

You can’t do anything to prevent it as the transmission of this genetic disease to the foetus is unfortunately random.

“We can, however, calculate the chance or percentage of the foetus being normal (no thalassemia), thalassemia minor or thalassemia major,” Dr Beh states. 

If one or both partners have the blood disorder, can anything be done to mitigate the impact on the baby?

“As mentioned, we can’t alter the risk of transmission,” Dr Beh notes. “However, prenatal tests can be done to detect thalassemia major in the foetus, as this serious form is the one that matters. Inheriting thalassemia minor is not a big problem, as one’s child can function normally, like their parents.”

If the anaemia is severe...and the patient is feeling unwell with breathlessness, extreme fatigue or giddiness, a blood transfusion may be recommended.

Does an expectant mother with thalassemia minor have to take special care during her pregnancy?

Dr Beh explains that this depends on the expectant mum’s haemoglobin level how severe her anaemia is and how it affects her.

“If the anaemia is severe, such as cases where one’s haemoglobin level is less than 8g and the patient is feeling unwell with breathlessness, extreme fatigue or giddiness, a blood transfusion may be recommended,” he elaborates.

He also recommends that the mum-to-be take sufficient folic acid supplements during pregnancy.

What are the treatment options, if any, for the mum and baby when it arrives?

Treatment for thalassemia major involves life-long regular blood transfusions to replenish the supply of healthy red blood cells in the body. Also, iron chelation therapy to remove the excess iron generated by the eventual breakdown of the transfused red blood cells.

“Recent medical advances like repeated intrauterine foetal transfusions have allowed the survival of some affected babies,” Dr Beh notes. “As for a potential cure, stem cell transplantation is required, which has been carried out in some centres with success.”

What is the worst-case scenario for mother and child with the condition?

“The worst-case involves the foetus having thalassemia major, especially Alpha-Thalassemia, resulting in a generally lethal foetal condition called Barts hydrops fetalis,” says Dr Beh. “This development can potentially lead to numerous maternal complications like severe preeclampsia.”

As this is a lifelong condition, how does one live with it?

Healthy living is key. You may have to modify your diet to avoid too much food that is rich in iron. This is because individuals with thalassemia already have an abundance of iron already built up from the higher rate of red blood cells breaking down, Dr Beh explains.

Also, folic acid, vitamin C-rich foods or supplements are recommended to maintain good health.

Photos: iStock

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